A known liquid ejection apparatus is configured to eject liquid from nozzles thereof. A liquid ejection apparatus, e.g., a multi-function device, includes a printer section configured to perform printing by ejecting ink from nozzles thereof. In the multi-function device, a carriage on which a liquid ejection head, e.g., a recording head, is mounted, is configured to move in a scanning direction while being guided by a guide portion, e.g., two guide rails. The two guide rails are fixed to a frame disposed below the guide rails. More specifically, the frame is a plate-like member including metallic material. The frame includes a bottom plate extending in the scanning direction and fixed to an upper surface of a base, e.g., a housing, including resin material. The frame further includes a side plate integrally provided with the bottom plate at each end of the frame in the scanning direction. The side plates are provided by bending the plate-like member upward with respect to the bottom plate. The two guide rails are fixed to upper end portions of the side plates. The side plates of the frame support a feeding roller configured to feed a recording sheet.
The resin material of the housing has a higher coefficient of linear expansion than the metallic material of the frame. Therefore, the housing readily expands and contracts, for example, with ambient temperature changes. However, as described above, the frame includes the bottom plate and the two side plates that are integrally provided by bending the plate-like member including the metallic material at each end thereof with respect to the scanning direction. The frame has a relatively high rigidity. Therefore, even when the housing is deformed, for example, with ambient temperature changes, the positional relationship between two side plates of the frame is unlikely to change. Accordingly, the positional relationship between the guide rails fixed to the side plates and the feeding roller supported by the side plates is unlikely to change. Consequently, the positional relationship between the recording head mounted on the carriage configured to move in the scanning direction while being guided by the guide rails, and a medium, e.g., a recording sheet, fed by the feeding roller is unlikely to change. Thus, reduction in the printing quality is prevented or reduced.
Nevertheless, the frame includes the bottom plate elongated in the scanning direction, so that the frame becomes relatively heavy in weight. Therefore, the liquid ejection apparatus including such frame becomes heavy in weight. A space is required in the printer section to place the bottom plate extending in the scanning direction. In view of reductions of weight and size of the liquid ejection apparatus, two separate members corresponding to the two side plates may be provided in place of the frame including the bottom plate and the two side plates. The two members may be fixed to the housing. In this case, however, there is not a portion corresponding to the bottom plate between the two members. Therefore, when the housing expands and contracts, for example, with ambient temperature changes, the positional relationship between the two members is likely to change. Therefore, the positional relationship between the feeding roller supported by the two members and the guide rails is likely to change. Consequently, the positional relationship between the liquid ejection head and the medium may change, so that the printing quality may possibly be reduced.